S&W 686 Misfiring

[detox]

About every few shots my 686 will misfire. I can see by looking at the Small Pistol primer that the primer was just barely hit by the firing pin. Cartidge will usually fire after second attempt. This gun does this with all primer brands thick and thin cup. Could it be a bad firing pin? Why would it do this every few shots? It does this only when sqeezing trigger for slow fire, single action (cocking hammer back before shooting), accuracy testing.

[USAFrox]

I'd guess you have a weak spring in need of replacing.

[44man]

Did you loosen the strain screw or put a lighter hammer spring in looking for a light trigger?

[wiljen]

I'd bet springs - buy a spring kit from Wolf and replace them and I'd bet the problem goes away.

[HATCH]

I would place bets the strain screw is loose.
Its located on the front of the grips.
get a screw driver that fits the screw slot tightly and tighten it till it doesn't turn any more.

[detox]

Thanks guys! I removed the Hogue grip and tightened the strain screw...it was loose about 1/2 turn. If this does not fix it may be spring. Gun is a stock unmodified revolver.

[Tatume]

You might want to loosen it, add a drop of thread sealer, and retighten. I think you've found your problem though.

[ReloaderFred]

The strain screw is most likely the problem, but also look at your primer seating to make sure that's not causing you problems. Ideally, your primers should be seated .004" below flush. This seats the anvil into the priming mix and allows for good detonation.

Hope this helps.

Fred

[detox]

I use the RCBS handheld priming tool. I will try to use more force to seat. Thanks

[km101]

You might want to loosen it, add a drop of thread sealer, and retighten. I think you've found your problem though.

I would bet money that this will fix the problem! S&W should do this to all the revolvers with this type mainspring before they leave the factory!

[Thin Man]

You found the strain screw backed out only 1/2 turn. It is rare that this amount of backing out the strain screw would result in the light hammer falls you are having. I would start by replacing both the mainspring and strain screw. Your mainspring may have been replaced with a "target only" light spring in the past, or the original spring altered in a manner that cannot be easily detected. Also, the end of the strain screw may have been shortened to reduce it's pressure on the mainspring, again for a lighter trigger pull weight. Replace both of these inexpensive parts at the same time (pay for shipping only once). If the problem persists, look for (1) debris in the strain screw channel in the front of the grip frame which would prevent the strain screw from closing down completely onto the mainspring, (2) debris or burrs or obstructions in the frame where the hammer travels toward the primed case - anything that would slow or prevent the hammer from falling completely into the frame, and (3) burrs or scars or other marks on the hammer and fire pin that indicate misalignment or dragging that would indicate a resistance to the free fall movement of the hammer traveling forward. You should be able to do most of this yourself, and if not get competent help where needed. Good luck with your project.
Thin man

[beagle]

When you really get down to the bottom of the barrel in searching for fixes, check the firing pin. I bought one of the S & W M29.44 Mag "silly wet" 10 5/8" barrel jobs when they first came out. New, out of the box, it would misfire about 2-3 times out of a cylinder full. My gunsmith, after trying everything else checked the firing pin. It was out of tolerance and striking light. Sent it back to Smith with a nasty letter and they replaced the firing pin and apologized for letting it get out like that. Of course, I don't know the history of yours. Mine was new./beagle

[sixshot]

Strain screw, plus be sure to try federal primers, in competition you will not find a single revolver shooter that uses anything but federal primers & yes everyone of us back off the strain screw as much as possible & still get 100% reliability.

Dick

[detox]

I purchased this gun new in 1995. Back then gun never misfired using CCI Magnum primers. I just recently started back shooting this gun after 15 years of being stored in safe and noticed this misfire condition started getting worse and worse. So i removed the Hogue grip and tightened the loose strain screw 1/2 turn till tight. I noticed the hammer spring tightening by just tightening 1/2 turn. I am sure the loose strain screw was the problem.

I shoot mostly lower powered 1000fps loads. Can the Federal primers be used in faster Magnum loads?

[fourarmed]

I did some primer tests once using H-110, which is said to be among the hardest pistol powders to ignite consistently. I used Federal LP, Winchester LP, and CCI LPM. I settled on WLP as both the others gave much larger velocity spreads. The Federal string (ten shots as I recall) was really consistent except for one shot, which put the spread up around 200fps. I suppose it could have been a chronograph error, but it scared me off of Federal standard primers with H-110.

[detox]

I would place bets the strain screw is loose.
Its located on the front of the grips.
get a screw driver that fits the screw slot tightly and tighten it till it doesn't turn any more.

I tightened screw and oiled gun well...Problem solved...no more misfires using CCI Small Pistol primers! Thanks guys

[ClemY]

I tightened screw and oiled gun well...Problem solved...no more misfires using CCI Small Pistol primers! Thanks guys

I'm glad you solved your problem, but there is another issue that can cause problems with misfiring. The frame mounted firing pin can be a bit shorter than is optimum for 100% ignition. I replace all my centerfire firing pins with slightly longer ones I get from Brownell's. They are also available from several other sources.